Updated at 20:15 BJT
ISIL has confirmed in a statement that the group's leader, Abu Bakr al-Baghdadi, is dead, Xinhua reported on Tuesday citing the website of Iraq's news agency al-Sumaria News.
Hours after Xinhua's report, the Syrian Observatory for Human Rights told Reuters that it had "confirmed information" that al-Baghdadi had been killed.
However, Iraqi authorities said no relevant information has been received and cannot verify the authenticity of the report yet. The Pentagon has also said that it "could not corroborate the death," according to Reuters.
The terrorist group confirmed the death of its leader al-Baghdadi in a brief statement through its media in the (ISIL-held) town of Tal Afar in the west of Mosul, without giving further details.
In the statement, ISIL said the name of a new "caliph" would soon be announced, said al-Sumaria citing an anonymous source from Nineveh Province.
According to the website, the announcement has caused a stir among supporters of the organization.
Abu Bakr al-Baghdadi making his first public appearance at a mosque in Mosul, according to a video recording posted on the Internet on July 5, 2014. /Reuters Photo
It was reported in June that Russia said there was a "high degree of certainty" that al-Baghdadi was killed in Russia-led airstrikes, but ISIL did not confirm this.
The claims were also questioned by the US.
The news report came a day after Iraqi Prime Minister Haider al-Abadi formally declared Mosul's liberated from ISIL after nearly nine months of fierce fighting to dislodge the extremist militants from their last major stronghold in Iraq.
Mosul, 400 kilometers north of Iraq's capital city Baghdad, came under ISIL control from June 2014, when government forces abandoned their weapons and fled, enabling ISIL militants to take control of parts of Iraq's northern and western regions.
(With inputs from Xinhua)